Size matters, especially for cathode blocks

Word filtering though to us in AZ China has it that the Chinese have made another breakthrough in cathode technology.

We understand that Qingxin Carbon, the cathode plant in Ningxia province right by the former Alcan smelter, has been able to develop a block which breaks new size records. the new block, which is now being installed in Chalco’s 600KA plant in Liancheng, has dimensions of 720*560*3990. This makes the blocks 20mm wider and 30mm higher than the blocks presently used at that smelter.

Going higher should in normal circumstances increase the life of the block. There is more carbon between the liquid metal and the collector bar in the bottom of the block. Whether that happens for Chalco Liancheng is a matter of conjecture, since the smelter is only 12 months old.

Going wider is something else. We aren’t quite sure yet what the targeted gain is. I consulted with a friend of mine who forgotten more about cathodes than I will ever know. He tells me there are several possible gains to be had.

one less block in the lining,

just increasing the length of the pot with all other changes being increased proportionally (probably the most likely)

thinner joints (there is a technology where they basically butt the blocks together with a thin layer of glue in the joint)

reduce the width of the large joint along the headwall of the pot.

Either way, it’s an interesting move from a strategic viewpoint. Qingxin was already the only cathode plant in China that could make blocks to the old size. With Chalco accepting this new size into their 600KA line (and probably working closely with Qingxin on dimensions and specifications), the chances for other cathode plants to crack the 500KA and 600KA market just became a lot harder.